1. Technical Field
This invention relates generally to technology for designing internal combustion engine components that involve fluid flow, and more particularly to a modular flow box that allows for more rapid modification of internal passages in the flow box without requiring alteration of the entire flow box and without altering critical passage terminal portions.
2. Discussion of the Prior Art
It is necessary in the design process of an internal combustion head to interactively change the physical design of the internal passages of such head. Such changes are made in response to flow evaluations (measurement of flow volume and turbulence) while using a flow box. Existing flow boxes, used in the automotive industry today, remake the entire flow box to accommodate any physical design change of the internal passage because such boxes are constituted of two parts divided along internal passages. Any subtle contour change of the internal passages often require the making of numerous flow boxes to progressively achieve the desired flow. If the box portions are made by NC machining, there will be significant remachining to progressively create the box parts. This is very costly, requires considerable material consumed in each of the several flow boxes, and is relatively slow as reflected by the great number of flow boxes that must be constructed. More importantly, each time an engine head flow box is constructed, valve seat machining variables can slightly change so that the new flow box will give an evaluation not directly comparable to the previous flow box that was used. Even if the box parts are fabricated without NC machining, such as by cubital forming (powder resin layers) or by stereolithography (paper laminations), the fabrication time is considerable.
A commonly assigned U.S. patent application, U.S. Ser. No. 08/158,054 filed Nov. 26, 1993, entitled "Rapidly Making A Contoured Part" discloses a technique for rapid prototyping parts having complex internal cavities by use of sectioning into blocks or slabs which can be rapidly cast or rapidly machined. Such technique, however, did not appreciate the need to achieve interlocking and accurate self-alignment between blocks or slabs that make up the assembly, such self-alignment being essential to the interactive remaking of a flow box.